The invention relates to a thermal break for frames of windows, doors, and other building components. Specifically, the invention relates to an thermal break insulating section for aluminum or other metallic windows, doors, and other building components.
According to the American Architectural Manufacturers Association (“AAMA”), improving the thermal performance of glazing systems has become increasingly important in recent years. See Structural Performance Poured and Debridged Framing Systems, Publication No. AAMA TIR-A8-90. There currently exist a number of design options to improve thermal performance. The primary method of improvement has been to include a thermal break in the framing system. A thermal break breaks the continuity of the framing system with the inclusion of a low conductance material thereby reducing conductivity of thermal energy. The reduction of conductivity is beneficial to a building's energy consumption properties. The reduction can also improve the resistance of framing members to condensation or frost formation. Further, the inclusion of a low conductance material providing a break in the framing system can have the desirable effect of improving the acoustical properties of the framing system. The desirability associated with improved acoustical properties is evidenced by the Federal Aviation Administration's program related to the reduction of Airport Nose Compatibility. See FAA Part 150, Airport Noise Compatibility Planning.
A significant segment of thermally broken glazing systems currently available use a thermal break design known in the art as “poured and debridged.” With respect to aluminum framing systems, for example, the aluminum exterior and interior framing portions are extruded as one piece. An elastomeric material acting as a thermal break can be poured into an extruded cavity connecting the interior and exterior framing portions of the one piece extrusion. The pouring in of said elastomeric material constitutes the “poured” portion of the “poured and debridged” design. After the elastomeric cured, the extruded bridge connecting the interior and exterior portions of the one piece extrusion is removed. Said removal constitutes the “debridging” aspect of poured and debridged designs. FIG. 1 shows a typical example of the one piece design, while FIG. 2 shows a poured and debridged one piece design. Other aspects of the “poured and debridged” design will be readily appreciated by the skilled artisan and are not specifically referred to herein, however, an explanation of additional relevant aspects of the “poured and debridged” design is provided in the above referenced AAMA publication.
Various problems exist that are associated with the poured and debridged process. For example, one piece designs require a multitude of dies for each desiring variation in the extrusion. Further, often architects and designers prefer to have the exterior portion of the framing system to be painted or anodized a different color from the interior portion of the framing system. To do so requires the manufacturer to take painstaking steps for example, the steps include masking one half of the one piece extrusion during painting or anodizing and then separately painting or anodizing said masked portion a separate color. Further, the debridging of one piece extrusion generates a great deal of waste. In the case of aluminum systems, high amounts of metal shavings must be discarded. There is also a cost associated with the labor needed to perform the debridging process. Further, the width of the thermal break is limited to the width of saw blades able to debridge one piece extrusions. Thus, limitations associated with saw blade widths translate into limitations of the width of the debridging cut, and ultimately, the width of the thermal break. Still further, the saws and other equipment necessary in the debridging process have a high cost of upkeep, and when being repaired, result in down time in the manufacturing of windows, doors, and other construction components.
As an alternative to poured and debridged systems, it is known to take two separately extruded portions (e.g. interior and exterior portions) of a framing system and join them through the use of a pre-manufactured polyamide plastic strip having glass fibers impregnated therein. Said strips provide the thermal break. However, those systems and methods still conduct thermal energy. Thus, there exists a need to reduce the thermal conductivity of these systems. There also exists a need to increase the structural properties of those systems. There also exists a need to widen the thermal break to decrease thermal conductance and to increase acoustical properties. However, to widen the thermal break requires that the break be additionally reinforced. This could be done by adding polyurethane or similar material as a reinforcement and a thermal barrier. However, polyurethane, as an example, binds poorly to polyamide plastic strips of the type mentioned above. It would be desirable to be able to provide a thermal barrier, polyurethane for example, in conjunction with a thermal break, the thermal barrier providing the structural reinforcement necessary for adding width to the thermal break. The greater widths that could be achieved decrease thermal conductance and increase the acoustical properties of the thermal break system.